On a cool, clear mid-October weekend six people were murdered in New Orleans. The killings brought the tally of the slain in the Crescent City this year to 163, above the total of 162 for the entirety of 2006. The following weekend three more people were murdered in New Orleans - on Saturday alone. With nearly two full months left in the year, it is looking like the homicide rate in New Orleans will substantially outpace 2006's near-record numbers, which themselves far eclipsed even gang-plagued, hopelessly violent cities like Compton, California.

Indeed, with a murder rate of nearly 70 per 100,000, New Orleans is now three times more dangerous than murder-plagued cities like Philadelphia (recently nicknamed "Killadelphia") and Baltimore (home to HBO's apocalyptically grim series The Wire). What's happened?

The New Orleans police department's top brass tends to place the blame for all of the city's criminal justice woes on Katrina, but it's well known that New Orleans was an extraordinarily dangerous place well before the hurricane made landfall. The crack cocaine wars of the late 1980s and early 1990s that made Washington, DC and New York City such hotbeds of street violence hit a particularly bloody crescendo in New Orleans.

During the mid-1990s New Orleans reigned as the nation's murder capital, a frenzy of violence and drug dealing fomented in part by a police force that had grown almost irredeemably corrupt. Indeed, in 1994 federal prosecutors indicted 10 New Orleans cops on drug trafficking charges. More dramatically, that same year a New Orleans officer named Len Davis was charged with ordering the murder of a woman who had filed a police brutality complaint against him.

So, when Richard Pennington was sworn in as top cop in New Orleans in 1994, he made eradicating police corruption a top priority. Mr Pennington also emphasised community policing and insisted that the New Orleans police department (NOPD) focus on high crime areas (or "hotspots"). The so-called Pennington Plan was astonishingly effective in bringing down the murder rate in New Orleans. By the late 1990s, New Orleans not only finally began experiencing the significant crime declines that had been occurring in major metropolises like Los Angeles and New York City, it also had the largest decrease in crime among 50 major US cities.

But by the early 2000s, crime began rising in New Orleans again. After a failed mayoral bid in 2002, Mr Pennington was out as police chief-he is now top cop in Atlanta-and the long-suffering criminal justice system in New Orleans began collapsing.

In recent years, the Orleans Parish district attorney's office has released hundreds of suspects under Article 701 of the Louisiana code of criminal procedure, which states that suspects cannot be held for longer than 60 days on felony arrest without an indictment. Reasons given for the lack of charges filed in 701 cases range from incomplete police reports to overburdened assistant district attorney's who were simply not able to file an indictment before the 60-day period expired. Unsurprisingly, the city's drug business began getting the message that felony crimes-even murder-would most likely end in a 701 release.

Pre-Katrina, there were a few hundred 701 releases per year. But after the storm, the trickle of 701 releases became a flood. In 2006 alone, there were nearly 3,000 such releases, a five- or six-fold increase over pre-flood levels.

Experts offer various explanations. Some cite the inexperience of Orleans Parish district attorney Eddie Jordan, who took office without ever trying a case in criminal court. Others cite inadequate case processing on the part of the New Orleans police department. In one quadruple murder, for example, a police report was a total of three pages.

Whatever the reason, 701-related laxity has become so common that New Orleans street hustlers have dubbed doing 60 days in jail for a killing a "misdemeanour murder." This was no exaggeration: in addition to the thousands of suspects being released under Article 701, the Orleans Parish district attorney's office secured just one conviction in the 162 murders committed in 2006. Worse still, the district attorney's violent offenders unit (VOU) which handles the city's most violent crime has recently been wracked by staff departures. Former prosecutors have publicly complained that they were forced to spend much of their time performing administrative tasks like photocopying.

Unsurprisingly, Mr Jordan - he finally resigned last week -attempted to portray the former prosecutors' complaints as merely sour grapes. But when a small New Orleans-based non-profit organisation called "Silence is Violence" announced on October 1 that it would provide an administrative assistant to the VOU, it became clear that the district attorney's office was indeed suffering from a profound lack of resources.

The district attorney's office faced a severe crisis of confidence under Jordan. Dozens of former employees were recently awarded a $3.7m judgment in a race discrimination claim filed in federal court in 2003. The former employees (who are white) claim that Mr Jordan (a former federal prosecutor who is New Orleans' first black district attorney) fired them because of their race. Mr Jordan asked New Orleans' city council to add the amount of the judgement to his office's 2008 budget so the sum can be repaid. Mr Jordan's office also warned that if it does not receive help, his office could be "forced to close" and will be "without sufficient assistant district attorneys to prosecute approximately 2,500 cases, which are currently awaiting trial."

The office is now run by interim district attorney Keva Landrum-Johnson, the first female district attorney in the history of New Orleans.

As the year comes to a bloody close, it seems that New Orleans is nearing the tipping point where it may become so violent that it is no longer livable at all. Certainly, the current murder rate is so high and the city's population so low (around 250,000, well below pre- Katrina population of about 500,000) that a significant chunk of the city is already simply being killed off.

Incredibly, the killing fields of New Orleans do not appear to rank high as a concern among state and local officials. The mayor, Ray Nagin, has been silent in the face of the sort of mass killing that occurred and often dismissive of it. This summer, he told a group of reporters that the murder rate "keeps the New Orleans brand out there."

The police chief, Warren Riley, isn't much different. Earlier this year, after the back-to-back murders of Harvard graduate and independent filmmaker Helen Hill and jazzman Dinneral Shavers (who appeared in Spike Lee's Katrina documentary When the Levees Broke), Mr Riley unveiled an anti-crime plan that was comprised of little more than random traffic stops. And Mr Riley was all-too-defensive recently when the New Orleans-based Metropolitan Crime Commission released a report urging the New Orleans police department to focus on violent offenders.

Perhaps the most serious blow to New Orleans' ailing criminal justice system is the recent election of former Republican Congressman Bobby Jindal as Lousiana's governor. Mr Jindal has boasted that he will turn New Orleans-which is already profoundly suffering from a lack of public resources-into a model of far right privatisation politics on such issues as education and healthcare.

So, New Orleans speeds along to the sort of wholesale destruction than even Katrina could not have wrought without anyone in major leadership positions stepping up to stop the bloodletting. "The trouble is," University of New Orleans criminologist Peter Scharf told me recently, "there is no willing to stand up and say 'This is fucking nuts.'"

· Ethan Brown is the author of Queens Reigns Supreme: Fat Cat, 50 Cent and the Rise of the Hip-Hop Hustler (Random House) and the forthcoming Snitch: Informants, Cooperators and the Corruption of Justice (Public Affairs). He lives in New Orleans.